Treatment patterns following next-generation sequencing in U.S. Veterans with metastatic cancer across social determinants of health.

Abstract

699 Background: Social determinants of health (SDoH) such as race, ethnicity, socioeconomic status (SES), and rurality affect access to cancer care. This study evaluated whether SDoH impacts systemic treatment patterns following next-generation sequencing (NGS) among Veterans with common cancer within the integrated U.S. Department of Veterans Affairs (VA). Methods: We conducted a retrospective cohort study of U.S. Veterans diagnosed with metastatic non-small cell lung cancer (NSCLC), colorectal cancer (CRC), or prostate cancer who received NGS testing between 2019 and 2023. Data were obtained from the VA Corporate Data Warehouse, VA Cancer Registry, and the National Precision Oncology Program (NPOP) database, which records the FoundationOne Tissue and Liquid CDx NGS data. For each cancer type, we assessed use of FDA approved systemic therapies (chemotherapy, immune checkpoint inhibitors (ICI), targeted, and hormone) as a first treatment following NGS testing. Associations between treatment utilization and SDoH, including self-reported race, ethnicity, age, gender, rurality, and SES, were examined using multivariable logistic regression to estimate odds ratios (OR) with 95% confidence intervals (CI). Results: Among 4,413 Veterans with metastatic cancer that received NGS testing, 97.3% were male and 67.2% White, with broad variation in rurality, income, and education. Overall, 76.9% received a systemic therapy following NGS testing, with 68.0% initiating treatment within 90 days. Chemotherapy (53.7%) was the most common in Veterans with CRC, followed by targeted therapy (20.4%) and ICI (2.3%). For patients with NSCLC, ICI (51.5%) had the highest use, followed by chemotherapy (8.0%) and targeted therapy (6.9%). The majority of Veterans with prostate cancer received hormone therapy (81.6%), followed by chemotherapy (6.4%), targeted therapy (1.6%), and ICI (0.6%). Patients with CRC had higher targeted therapy use in Veterans ≤65 years (OR 1.94, CI 1.19-3.19) but had no differences between SDoH. For NSCLC patients, ICI utilization was lower in female (OR 0.47, CI 0.27-0.82), multi-racial (OR 0.27, CI 0.09-0.77), and Asian (OR 0.21, CI 0.04-0.91) Veterans and patients residing in highly rural areas (OR 0.21, CI 0.05-0.81). Disparities were not observed in Veterans with prostate cancer receiving targeted therapy, but hormone therapy use was lower in patients ≤65 years (OR 0.51, CI 0.34-0.76) and higher in Hispanic (OR 5.09, CI 1.55-31.4) Veterans. Conclusions: Among NGS-tested Veterans, treatment patterns varied across SDOH with substantial adoption of ICIs in NSCLC, hormone therapy in prostate cancer and targeted therapies in CRC. Access to targeted therapies in prostate cancer appeared to be unaffected by SDOH. Future work will incorporate additional genomic platforms and biomarker specific analysis to identify drivers of treatment variation in the VA.